Ahhhh, I see. I had stupidly assumed that the supercap was keeping power for all settings.

My bad.

I'll see if I can source a replacement then - I usually order my electronic components from Farnell or RS so hopefully they'll have something suitable. I'll open up the shell of the A board again tomorrow and check the existing supercap's values.

I have issues with my SFZ3 980629 CPS2. I plugged it yesterday (haven't used it for a few years) and the sound was very low (RCA as well as JAMMA). I think i already had this issue, and maybe the VOL- hold during power fixed it (but can't remember for sure).

I tried several time but it doesn't change anything. I also uplugged/replugged the A/B boards. The volume shown in the test menu is "39" (max). I made a reset.
Also, is the TEST button supposed to do something ? Because the three buttons doesn't do anything.

I tried again today, and after a few try, i don't have sound at all anymore.

Do you think i can try to change this "supercap" ? I opened the A-Board and everything looks pristine.

Thanks. I checked my PSU (blast city) voltages and they are fine.
I hope the PSU is not frying everything because my gdrom also start only when he want to.

This is pictures of my A-Board. I will try to buy another to make tests. Is there anything i can try to troubleshot with my multimeter ?

About the TEST button on the A board, is it supposed to do something ? And when i push VOL UP or DOWN, am i supposed to see the level change in service sound test (jukebox). I can't have anything other than 39. I wonder if the buttons are working

That problem is likely caused by corrupted data inside the volume control chip. Data corrupted because the supercap isn't holding enough voltage to make the data survive a power cycle, yet it's not low enough to make it fully "evaporate". You have to replace the super cap. It's the small device with a Matsushita logo ( [M] ) which looks like a small battery near the TOSHIBA TC9185P IC. The big capacitor near the RCAs is a regular capacitor. It's big but not super (lol)

OK i thought the biggest was the "supercap"
I shorted the M cap (it was at 3.6v) until it gave almost 0.05v but still no sound when booting.
Do you think it can still be the issue and worth to unsolder it ? (can the game boot without the cap ?)

I've looked through this thread and see the supercap mentioned, however other system and game settings are being retained just fine so the supercap must be okay, the EEPROM in that case should also be fine.

The supercap is part of the audio circuitry only, has no effect on other settings. Your problem is likely the supercap.

I got a new motherboard and the sound is working. I wanted to be sure the game was ok before bothering trying. I will try to remove the cap.

edit : i noticed the TEST side button was also working on the new a-board. (it was not on my defective a-board but nobody told me if it was normal or not).
Jamma TEST pin is set correctly to GRND when pressing TEST on the cab, but not with the TEST button on the board (switch on bare motherboard). I looks like the three switches may actually be dead ! (not the green plastic part but the switches themselves)

edit 2 : it was easy to check since vol+ and vol- are also on the kick harness. Indeed the 3 switches are dead. I put the sound back with vol+ on the kick harness pins

Yes. It seems suspicious that all three switches are dead but it looks like it.

It's not entirely surprising to me. Those switches are notorious for being flaky or flat not working (likely due to dust/smoke build-up on the internal contacts). You could try shooting some non-lubricant "contact cleaner" into them and wiggling them all around to try to break up any rubbish inside them. If that doesn't do the trick, try this:

- Solder a piece of wire to GND
- Solder a piece of wire to the TEST button signal
- After the game is running, touch them together and see if TEST menu comes up

If it works, you know your switch is shot.
-ud

"Sin and death's got the whole world gettin' illa, but I praise God for the Blood Spilla."